I am trying to save some 4-bit images. Many of them only use 5 colors. However, these are going on a set-top box which requires that all 16 colors in a specific custom palette be indexed in the image I am trying to create.

Currently, if I use Fireworks to optimize an image, I can load the custom palette, optimize it for 16 colors, and export it as a 4-bit image. However, the entire 16 color palette is not being indexed in the image. It only indexes 5 colors.

How can I get Fireworks to index the entire 16 color palette when I export it as a 4-bit image?